Actually, there isn't any great backstory because the Sporkman archives aren't continuity. They also suck. You don't need to read them at all to understand anything in Flint. As such, I heartily DON'T recommend you read them.

See now, with the amount of time muckery Sporky went through, you could start from scratch anyway and just use that as an excuse. Besides, you're the one who left little inside jokes in the strip about Amanda's old friend the super-hero, hence prompting people like me to go back and read all the Sporkman archives.